The project is designed to explore the effect of cationization of antigens on the immunogenic and regulatory properties of those antigens. A variety of well established protein antigens will be cationized using ethylene diamine and carbodiimide to substitute amino groups for the carboxyl side chains on the proteins. The cationized proteins will be characterized biochemically and immunochemically, with particular attention given to the unique and shared properties of both native and cationized proteins. The immunogenicity of cationized proteins will be compared with that of the native molecules in mice and the cellular requirements for the immune response to these antigens will be explored. The regulatory properties of the cationized proteins will also be studied by administering these molecules to mice in various doses at various times before administration of an immunogenic dose of either native or charged protein. The cellular basis for such regulatory abilities, either help or suppression, will be explored via cell transfer experiments. Finally, possible cross reactive properties of the various cationized proteins which might be attributable solely to the charged determinants will be analyzed.